Displaytech, Inc.

Hoechst Aktiengesellschaft

Uwe Muller

Michael D Wand

David M Walba

William N Thurmes

Xin Hua Chen

Peter Cobben

Daniel J Dyer

Gunter Scherowsky

This invention provides LC compositions useful as birefringent materials in electrooptic devices which exhibit zero or low negatively sloped birefringence dispersioon (e.g., exhibiting positive birefringence dispersion significantly lower than that of currently available LC compositions) or more preferably positively sloped birefringence dispersion in which birefringence of the material increases with wavelength. The invention provides compounds useful as components of LC compositions which exhibit negative birefringence where n is higher than n . The compounds of this invention are dimers of LC-like compounds in which the monomers are linked to each other through a high birefringence moiety (dimerization linker). The LC monomers consist of an LC core and one or two tail groups. Preferred monomers for this invention have low birefringence in comparison to the birefringence of the monomer linking moiety. The dimers have normal positive birefringence dispersion to have birefringence that is lower in absolute value at longer wavelengths. But since they have negative birefringence, their birefringence actually increases (i.e., goes less negative) as wavelength increases.

Mesogenic materials with anomalous birefringence dispersion and high second order susceptibility (X(2))

This invention provides LC compositions useful as birefringent materials in electrooptic devices which exhibit zero or low negatively sloped birefringence dispersion (e.g., exhibiting positive birefringence dispersion significantly lower than that of currently available LC compositions) or more preferably positively sloped birefringence dispersion in which birefringence of the material increases with wavelength. The invention provides compounds useful as components of LC compositions which exhibit negative birefringence where n.sub.o is higher than n.sub.e. The compounds of this invention are dimers of LC-like compounds in which the monomers are linked to each other through a high birefringence moiety (dimerization linker). The LC monomers consist of an LC core and one or two tail groups. Preferred monomers for this invention have low birefringence in comparison to the birefrigence of the monomer linking moiety. The dimers have normal positive birefringence dispersion to have birefringence that is lower in absolute value at longer wavelengths. But since they have negative birefringence, their birefringence actually increases (i.e., goes less negative) as wavelength increases.

Mesogenic materials with anomalous birefringence dispersion and high

Ferroelectric, liquid-crystaline polymers contain repeating units of the formula (I) ##STR1## in which the symbols have the following meanings: B=a group having at least one chiral center, of the formula ##STR2## in which R.sup.6, R.sup.7 and R.sup.8 are identical or different and are H, CH.sub.3, OCH.sub.3, F, Cl or Br, and at least one of the groups R.sup.6, R.sup.7 and R.sup.8 must be H and X=H, F, Cl or Br and R.sup.9 =H or C.sub.1 -C.sub.10 -alkyl,

Ferroelectric, liquid-crystalline polymers, a process for their

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Berlin, Germany

Uwe Muller